I recently purchased a SCSI2SD V.5 adaptor (3.5″ and 2.5″) to replace a failing 1980s SCSI HD, and realized once I had it set up I could “image” the Micro-SD card to make boot-able images anyone could use.

Assumptions

Your classic 68k Macintosh turns on, and is prompting you to insert a disk. If your 68k Macintosh does not turn on, or does not show the insert disk icon, you may need to do some repair work before you proceed.

You have a SCSI2SD adaptor, you MAY be able to use these images with a Compact Flash card of the correct size and a CF2SCSI adapter, if you can, let me know.

You have a SD or MicroSD card you plan to use with your SCSI2SD adaptor.

1. Determine if you can use this method

This method will work for the majority of 68k Macintosh computers except: The 128K, 512K, 512Ke. These three 68k systems do not support internal or external SCSI. You will need to use one of the other setup methods I’ve previously identified, with the best option being buying and using Floppy-Emu to boot from 400KB SS SD floppy disk images.

This will work for the Macintosh Plus, but there is some extra work, see section 5 below.

In general for setting up your SD2SCSI card, I suggest either:

using one of the drive images I’ve provided, they include the drive’s boot and partition information, and minimum bootable versions of System 6.0.8 and System 7.5.5 (you can make them full versions yourself). Make sure you check that the size is equal to or less than the capacity of your card (see note for size in bytes under the table below).

using one of the smaller volume images I’ve provided as your SCSI 0 drive, and leaving the rest of your card for use as your secondary + drives (see section 3.2 below). For example if you have a 2GB card, you might want to use my 1GB image, and setup the rest of your card as a secondary drive (SCSI 1 etc), that’s what I did for my 32GB card,

3. Configuring your SCSI2SD adapter

You will need to configure your SCSI2SD adapter based on the size of SD or microSD card you plan to use. Since I do NOT have a SCSI2CF adapter I can’t provide any guidance for you, or know if you even have to do anything.

Remember to write the configuration information down. It is NOT stored to your SD CARD, it is stored on the SCSI2SD adapter. If you switch between cards with different configurations you will need to enter the proper drive sizes for the card before using it, or the “drives” will not be recognized, or worse get corrupted

Format the SD card you plan to use, if you are using windows I suggest doing a full format vs. a quick format to make sure the card is wiped clean and has no errors.

Download the correct setup software from CodeSRC, make sure you get the correct software based on your version of the adapter v3/v4/v5 vs. v6. The software is available for Windows 32, Windows 64, Linux and Macintosh OS X.

Run the setup software

Insert the SD or microSD card in to your SCSI2SD adaptor

Connect the USB cable from your computer to your SCSI2SD adaptor

3.1. If you want to setup your SD card as a single drive

Not recommended, but it’s up to you. Setting up your SD card as multiple hard drives will make your life simpler. Under the Mac OS, there are several limitations for what you can do to the drive the System files are installed on. By having at least 2 virtual drives you can save your self a lot of grief.Double check that the byte size of your SD card is equal to or greater than than the byte size of the image file you plan to use.

Select device 1

Set the sector size to 512

Set the sector count size based on the size of the image file, e.g. my 2GB image file is 1,971,322,880, so the sector count is 1,971,322,880 / 512 = 3850240

The device size should auto adjust, e.g. for the 2GB image file the size is 1.84 actual GB (a MB, GB etc. should be a multiple of 1024, but for marketing reasons storage uses a multiple of 1000)

You should be able to leave the rest of the settings as the default unless you have a reason to change the values (see Figure 1)

Select save to device

If you get the message “Save Failed” you’ve set the total sector size of your Device to be larger than what your card can hold.

Once saving is complete disconnect the USB cable from the SCSI2SD adapter

Eject the SD card from the SCSI2SD adapter go to section 4.

Figure 1: Device 1 configuration

3.2. If you want to setup your SD card as multiple drives:

Double check that the byte size of your SD card is greater than than the byte size of the image file you plan to use.

Follow the steps from section 3.1 above to setup device 1 based on the size of the image file you selected as your SCSI device 0.

Select Device 2 (Figure 3)

Select Enable SCSI Target

For SD card start sector, select Auto

For this example, because I used 1,971,322,880 bytes for device 1, I now have 13,823,377,408 bytes left to work with, which is equal 26,998,784 sectors.

Putting 26998784 sectors in to the sector count give me a Device 2 with a size of 12.874 GB (Figure 3).

If I wanted Device 2 to be smaller I’d reduce the sector size, and use the remaining sectors in Device 3 (and optionally 4)

I suggest that you leave about 50 to 100MB empty (100,000 to 200,000 sectors) un-allocated at the end of your SD card to prevent future issues if you want to backup and restore the contents of your SD card to a different SD card. As I mentioned earlier the available space on these cards isn’t standard, and can vary by 50 to 100MB.

Once you’ve finished setting up the Device tabs, press the Save to device button.

If you get the message “Save Failed” you’ve set the total sector size of your Device(s) to be larger than what your card can hold.

Once saving is complete disconnect the USB cable from the SCSI2SD adapter

5. Extra Steps for the Macintosh Plus

The Macintosh Plus doesn’t fully implement the SCSI standard, to get your SCSI2SD adapter to work you may need to provide extra power to the adapter through it’s USB port.

Also under the SCSI2SD card’s general settings:

Enable Unit Attention = OFF

SCSI Selection Delay = 0

Respond to short SCSI selection pulses = ON

Thanks to Huxley Dunsany for pointing out the settings, and James Thomson for confirming they worked on a 2nd system.

6. Another Option for setting up your SCSI2SD

Remember you could always start with one of my images set as SCSI 0, but once you have your SCSI 1 drive setup how you want, go back in to the SCSI2SD config software, and switch the SCSI IDs, so that my image becomes SCSI 1 (or later) and your newly created, partitioned drive becomes SCSI 0 (your boot drive). This will let you create a SCSI 0 boot drive partitioned exactly how you want.

Thank you very much! I can confirm that the instructions worked on macOS High Sierra and I was able to boot my Macintosh SE without a floppy. I should mention that dd took quite a while for me, around 3 hours.

Hi. This looks great, and I’m really looking forward to trying it out. Just our if curiosity, once this is set up, is there a way to write additional software to the SD card? There is lots of software one can download, but I’ve no way to write it to a floppy, so I’d love to be able to just write it directly to the SD card. Thanks!

I have the 5.1 board, and am running into issues getting the Mac (SE HDFD) to recognize the SCSI device. Is there any tips/tricks needed to get this going beyond setting the size & ID for the devices? Which firmware version(s) have you been successful with?

Another thing to do with the card: update the vendor/product/revision info so it masquerades as an Apple-original device (eg, the SEAGATE ST225N rev 1.0). The fields are case-and-position sensitive, so you can’t just drop in the names any old way (below, replace asterisk with a space):
vendor: *SEAGATE
product ID: **********ST225N
revision: 1.0*

With this config, the native Apple SC HD application will recognize the drives; you don’t have to use patched versions, etc., on those old machines that would otherwise ignore them.

Hi CT, not sure, have you modded you CC to 640×480? If so it should see your CC as an LC575 and work. For internal vs. external that’s up to you, when I had it installed in my un-modded CC I was using it internally.

Hey! Thanks for these guides, it was a great and complete set.
I like your 2GB image and would like to use it as a ‘starting point’. It seems quite complete. Two questions:

1) Is the RAM affected by the networking stuff on it or can that be further slimmed down?
2) Assuming I want to have several drives, the first one being your image and the others being simply empty 2GB drives for storage. I have SCSI2SD v6 and a Mac Classic II. How can I achieve this?

Hi Daniel,
1. the networking stuff isn’t enabled by default so there shouldn’t be an impact on your RAM. It’s on the image but would need to be installed.
2. You can write one of my images to the first part of your SD card, then set up the remaining parts of the card as additional drives following the instructions in section 3.2 of this post.

I wanted to start by first saying THANK YOU for these amazing guides and downloadable disk images – you’ve made it possible for me to get my Mac Plus running nicely with my new SCSI2SD, and I’m really grateful!

I did want to suggest a small addition to your guide – there are some details specific to the Mac Plus which caused me *days* of headaches, thinking I was missing something or doing something wrong. According to Codesrc (in a page which weirdly never came up for me in Google searches on this topic): “The Mac Plus is troublesome as it’s bootrom code doesn’t follow the SCSI standards. The SCSI standards recommend a SCSI selection abort timeout of 250ms, but the Mac Plus bootroms quit before even 1ms has expired.”

Make sure “Enable Unit Attention” is OFF
Change SCSI Selection Delay to 0
Enable “Respond to short SCSI selection pulses”

Until a kind person on the 68kMLA forum pointed that out to me, I was going in circles to the point of almost giving up – the Mac Plus would “see” the SCSI2SD, but only when I would boot from a floppy, and even then it was unstable and any software I tried to run from the SD card would lock up almost immediately. Making the changes noted above resolved everything instantly.

Could you go into more detail about how your SCSI2SD for the Macintosh Plus ?
Which disk image did you use ? I have copied the 2 go system 6.08 image but the Mac Plus is not seeing the SCSI2SD at all. There is no orange led showing up on boot so the Mac Plus isn’t seeing it.
Please tell me exactly what options you have checked and unchecked in the SCSI2SD setup utility. Thanks. James

I also saw someone mention they had to attached to their SCSISD to USB power while attached to their mac because the mac plus scsi bus wasn’t providing enough power… that could have just been an issue with their mac, but you could try that too.

I read that the 5.1’s termination is now software-controlled (using scsi2sd-util), I’m assuming you enabled it? The only other thing I’d suggest (if you haven’t tried already) is treating your SE as a Mac Plus and try providing usb power to your SCSI2SD adapter. See step 5. Extra Steps for the Macintosh Plus.

Thank you for your reply. I have now managed to get the SCSI2SD card to work with my Macintosh Plus.
I have a version 5 card which is smaller in physical size than the version 5.1 or version 6 cards. I have it plugged directly onto the DB-25 SCSI port on the rear of the Mac Plus using the internal IDC 50 pin to external DB-25 adapter designed by Michael McAllister. You also need to use a 25 pin male to male gender changer though so that you can plug it in directly into the rear of the Macintosh Plus. The problem I was having was that the SCSI2 SD card was not receiving any terminator power over the external SCSI bus so was not powering up at all. I then plugged it in via USB to power it up. I restarted the Macintosh Plus and it booted straight away ! Something to bear in mind is that the Macintosh Plus boots from ID 6 first so for the fastest boot time I would set the boot drive to ID6.
Apparently there is a simple diode and resistor mod which can be done to the Mac Plus which will enable it to provide SCSI terminator power as standard. I have been trying to find out more details about this mod but am having trouble finding anything. If anyone is aware of or has the technical details to perform this mod please do share it with this thread. Thank you once again for providing the bootable disk images.

Turns out that the Mac Plus, Mac Portable, 100-series PowerBooks, 500-series PowerBooks, and the PowerBook 1400 don’t supply SCSI termination power. So I’m assuming if you are using a SCSI2SD adapter with any of these you’ll need to provide power through USB. https://lowendmac.com/1999/scsi-termination-power/

For the mod I found:
Simple 4.7ohm resistor, and a regular 4001 diode from the 5V rail to the termination pin of the DB25 connector.

Hi Steve, followed your tutorial for creating disks for using with SCSI2SD. I have a 16GB card and since we were supposed to limit to 2GB I wondered how I could use the remaining 8GB, since the tool only let you setup 4.

Then I realized we’re actually creating virtual disks, right? Meaning while it would be good for the first to be 2GB to match your image, the rest don’t necessarily have to and I could partition them later into 2GB partitions?

I first tried to do the install myself from “floppies” (I have a Floppy Emu) but I was not successful, at some point it asks me for disk 1 again and just cancels the installation saying an error happened and my disk was left untouched… Maybe my install floppy images are bad at some point??

I just tried your 2GB image, writing it to the card under Windows with the recommended tool (why is it still seen as 16GB though? Is it because the “virtual disk” information only exists on the SCSI2SD device and it just reads and writes to/from the appropriate places? Anyway, writing the 2GB image file, and my LC III booted up 7.5.5 just fine!

Anything you could recommend to learn about the OS? I have never installed one of these in my life (or really used old macs in the past either).

One thing I need to figure out which I don’t find on your image is the memory control panel to enable 32-bit addressing and that the OS stops using all my mem (I expanded the LCIII with 32MB for a total of 36MB)

Hi Walter, from your message it looks like you got to the point where you were able to boot. Congratulations.
For your question about the memory control panel. I was only able to include a minimal version of 7.5.5 on my image (copywrite). But I do have another page on my site that explains how to update my images with the full version. See http://www.savagetaylor.com/2018/09/02/setting-up-your-vintage-classic-68k-macintosh-installing-the-full-version-of-system-7-5-5-or-6-0-8/
I updated this post to more clearly explain that the images can/should be updated before they are copied over.
Yes, you are right about the virtual disks. Each of my images acts as a physical “disk” and using SCSI2SD each disk gets it’s own SCSI ID. You can set up the remaining space on your SD card using the SCSI2SD control panel however you wish up to a max of 3 other “drives”, each of those “drives” can be larger than 2GB. E.g. a 8GB drive that you partition in to 4 2GB partitions.
For learning about the OS, I’m not sure, I first learned about using these back in the 90s, so I’ve never really looked for how to guides, I’ve been more focused on keeping a couple alive 🙂

I struggled through setting up my first SCSI2SD Board ina IIsi. Once I figured out what I was doing and set it up successfully, I was able to do a second IIsi in about an hour. I am now trying to do a G3, and am having a bear of a time getting the G3 to recognize more than 4 GB of the second partition. I have a 512 GB SD card installed. Everything is configured correctly and at first it recognized both of my partitions, 1 @ 2 GB and the second @ 500 GB. I made the small partition for the OS (8.6) and Apps and left the other for everything else. Everything was going great until I tried to install Retrospect (Backup Software). Then the G3 crashed and upon restart told me my large partition was unreadable and asked to initialize it. I figured why not, there’s nothing on it? So I did. It at first wouldn’t do anything at all because “Disk First Aid can not make changes to an unsupported drive.” I have the patched version of Drive setup and Lido 7, so I eventually did get it reinitialized. But, even though Disk first aid “sees” 500 GB of free space, it will only allow me to have a 4GB partition. I can’t enlarge it. I am stuck. I don’t know what to do. I have OS 8.6 installed, so the 2 GB partition limit doesn’t apply. Any ideas?

One thing I can suggest is do a full format/verify of the 512GB card to make sure there isn’t any defects. I’ve had issues before that turned out to be a bad card. I personally haven’t used a card of that size with a SCSI2SD, I don’t think there is an upper size limit, but I’d have to check.

Wanted to thank you so much for this incredible resource that you have put online. Immensely helpful. I set up my SCSI2SD on my Mac SE/30 and I downloaded your 500MB 7.5.5 disk image and dd’d it on to an 8GB SD card and it booted up on the SE/30 like a dream! Flawless.
However, I was wondering, I created a disk image (High Sierra sees it as a textedit document?) of the full version of 7.5.5 using basiliskII and it boots up without any problems in basiliskII.
But when I try to DD this file to an SD card and put in the SCSI2SD in the SE/30 no dice.
Likewise, if I try to boot your disk images in to basiliskII then it doesn’t boot up either.

So I was wondering what is the difference between my disk image that I created in emulation with basiliskII and your disk images and why can the SE/30 only read one and basiliskII can only read the other?

Would greatly appreciate any insight, I am by no means an IT expert, simply a hobbyist (SE/30 came out 5 years before I was born haha..)

Thank you for your invaluable documentation efforts!:)
However, I’m struggling to make this work on my Quadra 700. After switching IDs (from the 1.9GB scsi2sd disk where I’ve copied your OS755 image and successfully booted from, to the 1.6GB disk I’ve initialized and partitioned using the patched HD SC Setup and to where I’ve installed OS 8.1).

After switching IDs, making ID 0 the disk with the OS8.1. installation, I either get a “bus error” after the OS starts loading or it just hangs if I try to boot with extensions disabled.

Any ideas? I have a very standard Quadra with 64MB of memory. No additional cards installed. 100% stable running OS 7.6.1 from its original IBM SCSI drive.

I actually haven’t tried installing anything later than 7.5.5 yet, I might be able to test in a week or so, I’m currently finishing up some entries relating to the MacPlus. I’ve had a few requests to create a pre-made System 8.1 and System 7.6.1 images, but I haven’t looked in to the legalities of doing so, I know I can have minimum versions of 6.x and 7.x because they were often include on bootable disks and CDs, but I don’t know if that is the case for the later Systems.
For your SCSI2SD settings, based on your descriptionI’m assuming that you started with:
Device 1 = SCSI 0 = my 7.5.5 image
Device 2 = SCSI 1 = disk you initialized and installed OS 8.1 on.
You then changed Device 1 to SCSI 1, and Changed Device 2 to SCSI 0.
One thing you could try instead, switch back to the originally SCSI ids, and then you the utility I include called: System Picker. See if it lets you select the OS 8.1 system folder, if it does, you should be able to set it as the default system to start with.

Thanks a lot for your answer. I did end up upgrading your OS755 image to OS81 in Basilisk. It worked like a charm!;) I still have a smaller 1.6GB SCSI 1 but won’t touch it for the time being.

Next steps:
– setup LAN using an m0437 (LEDs blink but DHCP or fixed IP don’t seem to work; router doesn’t even show a new MAC address; I had the same behaviour with OS7.6.1 but was hoping that OS8.1 would solve it).
– setup Personal LaserWriter 300 (can’t find drivers for it; “https://www.macintoshrepository.org/8435-misc-mac-drivers-1990-1997-” only has an empty folder for this printer)

I’m currently working on a networking post for my ASANTE scsi2ethernet adapter.
I’ve not had any luck with DHCP, I had to manually set the IP of my mac, manually set the gateway IP (usually your main router), and the DSN, I used google’s 8.8.8.8. For my router it only dynamically assigns IP addresses from 100 to 255. So any fixed IP I use has to be below 100, so I use 192.168.1.68
Even with when connected and working (I use FTP) I don’t see any of my connected Mac’s listed as one of the connected devices in my router. I’ve got networking working for my Plus, SE, LCIII, LC475 and Colour Classic, under 6.08 for the Plus and SE, and 7.5.5 for the rest.